The present invention relates to substituted benzenesulfonamide and pyridinesulfonamide compounds, to herbicidal compositions containing the compounds, and to the utility of the compounds for the control of unwanted vegetation.
The control of unwanted vegetation by means of chemical agents, i.e., herbicides, is an important aspect of modern agriculture and land management. While many chemicals that are useful for the control of unwanted vegetation are known, new compounds that are more effective generally, are more effective for specific plant species, are less damaging to desirable vegetation, are safer to man or the environment, are less expensive to use, or have other advantageous attributes are desirable.
Many substituted benzenesulfonamide compounds are known and certain of them are known to possess herbicidal activity. For example, certain N-([1,2,4]triazolo[1,5-a]pyrimidin-2-yl)benzenesulfonamide compounds and their herbicidal utility were disclosed in U.S. Pat. No. 4,638,075 and certain N-([1,2,4]triazolo[1,3,5]triazin-2-yl)benzenesulfonamide compounds were disclosed in U.S. Pat. No. 4,685,958. In addition, certain N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl) benzenesulfonamide, N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl)pyridinesulfonamide, N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)benzenesulfonamide, and N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)pyridinesulfonamide compounds were disclosed in U.S. Pat. No. 5,858,924. Certain N-phenyl arylsulfonamide compounds are also known and are known to possess herbicidal activity. For example, certain N-(substituted phenyl)[1,2,4]triazolo[1,5-c]pyrimidin-2-sulfonamide compounds were disclosed in U.S. Pat. No. 5,163,995 and certain N-(substituted phenyl)[1,2,4]triazolo[1,5-a]pyridin-2-sulfonamide compounds were disclosed in U.S. Pat. No. 5,571,775.
It has now been found that a class of novel N-(5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidin-2-yl) arylsulfonamide compounds are potent herbicides for the control of unwanted vegetation by either preemergence or postemergence application. The invention includes N-(5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidin-2-yl)benzenesulfonamide and pyridinesulfonamide compounds of Formula I: 
wherein
Q represents N or Cxe2x80x94H;
A and B independently represent H, halo, R, ORxe2x80x2 or CO2Rxe2x80x3 with the proviso that A and B are not both H;
D represents H, halo, or R;
T represents H, SO2Rxe2x80x3, C(O)Rxe2x80x3, C(O)ORxe2x80x3, C(O)NRxe2x80x32, or CH2CH2C(O)ORxe2x80x3;
R represents C1-C3 alkyl each optionally possessing up to the maximum possible number of fluoro substituents;
R represents C1-C4 alkyl, C3-C4 alkenyl, or C3-C4 alkynyl each optionally possessing up to the maximum possible number of fluoro substituents; and
Rxe2x80x3 represents H or C1-C4 alkyl
and, when T represents H, the agriculturally acceptable salts thereof.
Compounds wherein Q represents each of N and Cxe2x80x94H are among the preferred compounds of the invention. T most preferably represents H. Some of the preferred compounds further possess an ortho methoxy substituent (A or B) in combination with a variety of substituents in the other ortho position (A or B) and hydrogen in the meta position (D); an ortho methoxy substituent (A) in combination with hydrogen or a meta methyl or chloro substituent (D) and no substituent in the other ortho position (B); or an ortho trifluoromethyl substituent (B) in combination with a variety of substituents in the other ortho position (A) and hydrogen in the meta position (D).
The invention further includes compositions containing herbicidal amounts of compounds of Formula I in combination with one or more agriculturally acceptable adjuvants or carriers and the use of the compounds of Formula I as herbicides. The use of suitable compounds of the invention to achieve total vegetation control is generally preferred. Both grassy and broadleaf weeds can be controlled. Post-emergence application of the compounds to undesirable vegetation is generally preferred.